diff options
| author | Arnd Bergmann <arnd@arndb.de> | 2010-06-01 22:53:01 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-08-10 13:47:43 -0700 |
| commit | ec79d6056de58511d8e46d9ae59d3878f958dc3e (patch) | |
| tree | 8e73cf399c4cb3c31dbf3caced385cfc018a706a /drivers/char/tty_ldisc.c | |
| parent | 3f582b8c11014e4ce310d9839fb335164195333f (diff) | |
tty: replace BKL with a new tty_lock
As a preparation for replacing the big kernel lock
in the TTY layer, wrap all the callers in new
macros tty_lock, tty_lock_nested and tty_unlock.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/char/tty_ldisc.c')
| -rw-r--r-- | drivers/char/tty_ldisc.c | 24 |
1 files changed, 13 insertions, 11 deletions
diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c index 500e740ec5e4..97681ffd6cbd 100644 --- a/drivers/char/tty_ldisc.c +++ b/drivers/char/tty_ldisc.c @@ -440,6 +440,8 @@ static void tty_set_termios_ldisc(struct tty_struct *tty, int num) * * A helper opening method. Also a convenient debugging and check * point. + * + * Locking: always called with BTM already held. */ static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld) @@ -447,10 +449,10 @@ static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld) WARN_ON(test_and_set_bit(TTY_LDISC_OPEN, &tty->flags)); if (ld->ops->open) { int ret; - /* BKL here locks verus a hangup event */ - lock_kernel(); + /* BTM here locks versus a hangup event */ + tty_lock_nested(); /* always held here already */ ret = ld->ops->open(tty); - unlock_kernel(); + tty_unlock(); return ret; } return 0; @@ -553,7 +555,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) if (IS_ERR(new_ldisc)) return PTR_ERR(new_ldisc); - lock_kernel(); + tty_lock(); /* * We need to look at the tty locking here for pty/tty pairs * when both sides try to change in parallel. @@ -567,12 +569,12 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) */ if (tty->ldisc->ops->num == ldisc) { - unlock_kernel(); + tty_unlock(); tty_ldisc_put(new_ldisc); return 0; } - unlock_kernel(); + tty_unlock(); /* * Problem: What do we do if this blocks ? * We could deadlock here @@ -594,7 +596,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) mutex_lock(&tty->ldisc_mutex); } - lock_kernel(); + tty_lock(); set_bit(TTY_LDISC_CHANGING, &tty->flags); @@ -607,7 +609,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) o_ldisc = tty->ldisc; - unlock_kernel(); + tty_unlock(); /* * Make sure we don't change while someone holds a * reference to the line discipline. The TTY_LDISC bit @@ -633,14 +635,14 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) flush_scheduled_work(); mutex_lock(&tty->ldisc_mutex); - lock_kernel(); + tty_lock(); if (test_bit(TTY_HUPPED, &tty->flags)) { /* We were raced by the hangup method. It will have stomped the ldisc data and closed the ldisc down */ clear_bit(TTY_LDISC_CHANGING, &tty->flags); mutex_unlock(&tty->ldisc_mutex); tty_ldisc_put(new_ldisc); - unlock_kernel(); + tty_unlock(); return -EIO; } @@ -682,7 +684,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) if (o_work) schedule_delayed_work(&o_tty->buf.work, 1); mutex_unlock(&tty->ldisc_mutex); - unlock_kernel(); + tty_unlock(); return retval; } |